Umahara Takahiko, Uchihara Toshiki, Yagishita Saburo, Nakamura Ayako, Tsuchiya Kuniaki, Iwamoto Toshihiko
Department of Geriatric Medicine, Tokyo Medical University, and Department of Laboratory Medicine and Pathology, Tokyo Metropolitan Matsuzawa Hospital, Japan.
Neurosci Lett. 2007 Mar 6;414(2):130-5. doi: 10.1016/j.neulet.2006.12.026. Epub 2006 Dec 27.
Immunolocalization of 14-3-3 protein isoforms, one of the interacters with ataxin 1, was investigated in spinocerebellar ataxia type 1 (SCA 1) brains using isoform-specific antibodies. Samples from the pons and from the cerebellum of four SCA1 cases and three controls were studied. The intensity of the immunoreactivity (IR) and its subcellular topography were analyzed. In control subjects, granular immunoreactivity for an epitope common to all known isoforms of 14-3-3 proteins (14-3-3 COM) found in the cytoplasm of some pontine and dentate nucleus neurons was weak. It was observed in some Purkinje cells, while its intensity varied. Many nuclei of those neurons and Purkinje cells of SCA1 were intensely immunopositive for 14-3-3 COM, while it was less in their cytoplasm. Expanded polyglutamine epitope was colocalized to 14-3-3 COM epitope in some pontine neurons, sometimes accumulated in intranuclear inclusion-like structures. This findings support previous reports that 14-3-3 proteins stabilize mutant ataxin 1 in nucleus and possibly lead to neurodegeneration. However, nuclear localization of 14-3-3 proteins in SCA1 brains was dependent on its isoforms, i.e. pontine neurons intensely positive for beta, Purkinje cells for tau and dentate nucleus neurons for both, while all of those neurons were consistently positive for zeta isoform, although sigma isoform tended to be located in the cytoplasm. Nuclear accumulation and isoform- and region-dependent subcellular localizations of 14-3-3 proteins may be related to SCA1 pathology, which exhibits marked regional variability.
使用亚型特异性抗体，在1型脊髓小脑共济失调（SCA1）患者大脑中研究了与ataxin 1相互作用的蛋白之一——14-3-3蛋白亚型的免疫定位。研究了4例SCA1患者和3例对照者脑桥和小脑的样本。分析了免疫反应性（IR）的强度及其亚细胞定位。在对照受试者中，在一些脑桥和齿状核神经元的细胞质中发现的14-3-3蛋白所有已知亚型共有的一个表位的颗粒免疫反应性较弱。在一些浦肯野细胞中观察到了这种反应性，但其强度有所不同。SCA1患者的许多此类神经元和浦肯野细胞的细胞核对14-3-3 COM呈强免疫阳性，而其细胞质中的阳性较弱。在一些脑桥神经元中，扩展多聚谷氨酰胺表位与14-3-3 COM表位共定位，有时积聚在核内包涵体样结构中。这些发现支持了先前的报道，即14-3-3蛋白在细胞核中稳定突变型ataxin 1，并可能导致神经退行性变。然而，SCA1患者大脑中14-3-3蛋白的核定位取决于其亚型，即脑桥神经元对β亚型呈强阳性，浦肯野细胞对tau亚型呈强阳性，齿状核神经元对两者均呈强阳性，而所有这些神经元对zeta亚型始终呈阳性，尽管sigma亚型倾向于位于细胞质中。14-3-3蛋白的核积聚以及亚型和区域依赖性亚细胞定位可能与SCA1病理学有关，SCA1病理学表现出明显的区域变异性。
